1. Field
This invention relates generally to telecommunications, more specifically, to a method and system to provide location information for voice calls.
2. Related Art
Around the world there are many emergency telephone numbers. For example, in the United States of America, the three-digit telephone number “911” is designated as the universal emergency telephone number. In the case of an emergency, a person can call 911 to reach an operator who can dispatch appropriate emergency services. To help provide the timeliest response, it is helpful and often necessary to have the location of the caller reported to the emergency service dispatcher. This is feature is of utmost importance when the caller is a young child, someone who is very ill or injured or otherwise unable to effectively communicate their location to the emergency services dispatcher. For these services to function properly, the telephone service provider must have means of identifying and reporting the location of the emergency caller.
In a typical scenario, when a subscriber subscribes to a residential telephone service from a service provider, the service provider assigns a telephone number for that subscription and allocates an access line to the subscriber's residence for the service. The access line connects to a telephone system of the residential telephone service. A user connects a telephone to the access line and uses the telephone to receive the residential telephone service.
The location of the subscription is the connecting point of the access line and the telephone. The location is typically the street address of the subscriber's residence. The service provider submits the telephone number and the location of the subscription to create a record in an Automatic Location identity (ALI) database. The record maps the telephone number to the location of the subscription. One of the usages of ALI database is for Emergency call purpose.
When a caller uses the telephone to make an emergency call by dialing “911”, the telephone system determines the telephone number associated with the subscription. The telephone system sends a call request to a 911 selective router telephone system. The call request includes the telephone number.
The 911-selective router telephone system receives the telephone number in the call request and retrieves from the ALI database the location of the subscription based on the telephone number. The location is presumably where the caller of the emergency call is. The 911-selective router telephone system uses the location to select a Public Safety Answering Point (PSAP), which is a telephone system. The 911-selective router telephone system further sends the emergency call request to the PSAP. The call request also includes the telephone number.
The PSAP presents the emergency call to an emergency call agent. The PSAP also retrieves from the ALI database the location of the subscription based on the telephone number in the emergency call request, and informs the emergency call agent of the location from which the call originated. The agent uses the location to dispatch emergency personnel and services.
Recently, various service providers have been rolling out new telephone services. These telephone services include cellular telephone services, and Voice over IP (VoIP) telephone services. Although these telephone services are not the same as traditional residential telephone services, they are either marketed as residential telephone services or subscribers use them as if they are equivalent to residential telephone services. Many consumers mistakenly assume that 911 or emergency services will be available in these new telephone services as they are in traditional residential telephone services. However this is often not the case. Cellular and VoIP telephone services, due to their ability to move from one physical location to another, present a fairly complex problem when it come to providing emergency call services. Especially when those services are highly dependent on knowing from whence the emergency call is being made.
In the case of VoIP telephone service, a user receives VoIP telephone service by connecting an IP telephone to a VoIP telephone system via the Internet. In one scenario, the IP telephone may be connected to a home DSL broadband Internet access gateway. It is also possible to connect the same IP telephone to a neighbor's Cable Modem broadband Internet access gateway. As a further convenience, is it also possible to connect an IP telephone to the IP network of a hotel during an out-of-town trip. In each example, the IP telephone is used to receive VoIP telephone service. While the convenience of being able to travel to any location with an appropriate Internet access, there is a danger associated with assuming that emergency services will be available on the IP telephone as on a regular telephone. To illustrate this danger, consider the following scenario.
While out of town, a user has an accident or encounters an emergency. The user calls 911 on an IP telephone that they have brought from home. The user assumes the 911-emergency call center would know her location, and expects emergency services to arrive in a short period of time. When the emergency call is not answered or when emergency services do not arrive in an hour, the user panics. Whilst in the hotel, the user's spouse calls the user's IP telephone number from their home concerned that emergency services were dispatched to their home for her whilst she is away. From the IP telephone service, the emergency dispatch services had no way of knowing her location.
As shown in the new telephone services, there is a need for a fundamentally new solution to provide the correct location of a caller during an emergency call.